The present disclosure relates to the field of light detecting technology, in particular to a light detecting device, a light detecting method and a display device.
At present, an APS (Active Pixel Sensor) circuit is used to detect an optical signal emitted by a light source. However, brightness of the light emitted by the light source may fluctuate, i.e., optical signal can include noise. For example, a backlight source of an LCM (Liquid Crystal Module) that drives an LED (Light Emitting Diode) by a current, so as to generate light, may have slight variations due to current noise. Consequently, the slight variations may be detected by a sensitive light detecting device and generate noise.
Optical fingerprint recognition technology mainly utilizes the principles of refraction and reflection of light. When a finger presses on a surface of a touch screen of a display device, a built-in light source of the display device projects light rays onto uneven fingerprint lines (i.e., valleys or ridges) of fingers. Since the light rays have different refraction angles and reflection intensities at pits and bumps on the lines, different currents may be generated when these light rays are projected onto a light sensitive sensor. By detecting these currents, positions of valleys and ridges on the fingerprint may be recognized, thereby making it possible to obtain a fingerprint image. However, in related art, when a finger touch on the touch screen has been detected, fingerprint recognition is further required. Since fingerprint recognition requires the determination of valleys and ridges, but the difference between the brightness of light corresponding to the valley and the brightness of light corresponding to the ridge is relatively small, any fluctuation in the light source at this time can have a greater impact on the identification of valleys and the ridges.